Signal demultiplexing device and signal routing device in high speed transmission system

Abstract

In a signal demultiplexing device formed by a probe light source, a wavelength converter, and a wavelength demultiplexer, the probe light source is formed by a plurality of sub-probe light sources configured to respectively generate the sub-probe lights with the prescribed different wavelengths for respective time-slots, a multiplexer configured to multiplex the sub-probe lights generated by the plurality of sub-probe light sources, and a phase different giving unit configured to give phase differences corresponding to time-slot positions to the sub-probe lights multiplexed by the multiplexer, and to sequentially output the sub-probe lights with the phase differences in correspondence to respective time-slots.

What is claimed is:  
     
       1. A signal demultiplexing device in a high speed transmission system, for time division demultiplexing high speed multiplexed signal lights in which signal lights with a prescribed identical wavelength are time division multiplexed in terms of time-slots, by converting the high speed multiplexed signal lights into low speed wavelength division multiplexed signal lights, the signal demultiplexing device comprising: 
       a probe light source configured to generate probe lights formed by a series of sub-probe lights with prescribed different wavelengths for respective time-slots, in synchronization with the high speed multiplexed signal lights;  
       a wavelength converter configured to receive the probe lights from the probe light source and the high speed multiplexed signal lights, and to convert the prescribed identical wavelength of the high speed multiplexed signal lights in each time-slot into a prescribed wavelength of a probe light in a corresponding time-slot so as to obtain wavelength division multiplexed signal lights; and  
       a wavelength demultiplexer configured to wavelength division demultiplex the wavelength division multiplexed signal lights obtained by the wavelength converter, and to output demultiplexed signal lights;  
       wherein the probe light source has  
       a plurality of sub-probe light sources configured to respectively generate the sub-probe lights with the prescribed different wavelengths for respective time-slots;  
       a multiplexer configured to multiplex the sub-probe lights generated by the plurality of sub-probe light sources; and  
       a phase different giving unit configured to give phase differences corresponding to time-slot positions to the sub-probe lights multiplexed by the multiplexer, and to sequentially output the sub-probe lights with the phase differences in correspondence to respective time-slots; and  
       the phase difference giving unit comprises:  
       a modulator for collectively modulating the sub-probe lights multiplexed by the multiplexer;  
       a first fiber grating for reflecting only a sub-probe light with a first wavelength and passing other sub-probe lights with wavelengths other than the first wavelength among the sub-probe lights modulated by the modulator;  
       a plurality of grating/delay pairs connected in series to which the other sub-probe lights passed by the first fiber grating are entered, an i-th grating/delay pair including: a delaying element for delaying those sub-probe lights that are passed by an (i−1)-th fiber grating, for a half of a prescribed phase difference between adjacent time-slots; and in i-th fiber grating for reflecting only a sub-probe light with an i-th wavelength and passing remaining sub-probe lights with wavelengths other than the i-th wavelength among those sub-probe lights that are delayed by the delaying element, where i is an integer greater than one, such that all of the sub-probe lights with the prescribed different wavelengths are reflected by the first fiber grating and fiber grating of the plurality of grating/delay pairs; and  
       a circulator for inputting the sub-probe lights modulated by the modulator into the first fiber grating, and outputting the sub-probe lights reflected from the first fiber grating and the fiber gratings of the plurality of grating/delay pairs as the probe lights.  
     
     
       2. A signal demultiplexing device in a high speed transmission system, for time division demultiplexing high speed multiplexed signal lights in which signal lights with a prescribed identical wavelength are time division multiplexed in terms of time-slots, by converting the high speed multiplexed signal lights into low speed wavelength division multiplexed signal lights, the signal demultiplexing device comprising: 
       a probe light source configured to generate probe lights formed by a series of sub-probe lights with prescribed different wavelengths for respective time-slots, in synchronization with the high speed multiplexed signal lights;  
       a wavelength converter configured to receive the probe lights from the probe light source and the high speed multiplexed signal lights, and to convert the prescribed identical wavelength of the high speed multiplexed signal lights in each time-slot into a prescribed wavelength of a probe light in a corresponding time-slot so as to obtain wavelength division multiplexed signal lights; and  
       a wavelength demultiplexer configured to wavelength division demultiplex the wavelength division multiplexed signal lights obtained by the wavelength converter, and to output demultiplexed signal lights;  
       wherein the probe light source has  
       a plurality of sub-probe light sources configured to respectively generate the sub-probe lights with the prescribed different wavelengths for respective time-slots;  
       a multiplexer configured to multiplex the sub-probe lights generated by the plurality of sub-probe light sources; and  
       a phase different giving unit configured to give phase differences corresponding to time-slot positions to the sub-probe lights multiplexed by the multiplexer, and to sequentially output the sub-probe lights with the phase differences in correspondence to respective time-slots; and  
       the phase difference giving unit comprises:  
       a modulation signal generator for generating a plurality of modulation signals in which an (i+1)-th modulation signal has a wavelength which is a half of a wavelength of an i-th modulation signal, where i is an integer; and  
       a plurality of wavelength dependent modulators connected in series, for modulating the sub-probe lights multiplexed by the multiplexer by using the modulation signals, wherein the i-th modulation signal is supplied to an i-th wavelength dependent modulator, a first wavelength dependent modulator modulates a first half of the sub-probe lights at a first half period of a first modulation signal and modulates a second half of the sub-probe lights at a second half period of the first modulation signal, and a j-th wavelength dependent modulator modulates a half of the first half and a half of the second half of the sub-probe lights modulated by a (j−1)-th wavelength dependent modulator at a first half period of a j-th modulation signal and modulates a remaining half of the first half and a remaining half of the second half of the sub-probe lights modulated by the (j−1)-th wavelength dependent modulator at a second half period of the j-th modulation signal, where j is an integer greater than one, such that the sub-probe lights with wavelengths corresponding to respective time-slots are sequentially outputted from a last wavelength dependent modulator as the probe lights.  
     
     
       3. A signal routing device in a high speed transmission system, for time division demultiplexing high speed multiplexed signal lights in which signal lights with a prescribed identical wavelength are time division multiplexed in terms of time-slots, by converting the high speed multiplexed signal lights into low speed wavelength division multiplexed signal lights, and for outputting signal lights by distributing signal lights with desired wavelengths that constitute the low speed wavelength division multiplexed signals into desired time-slots according to routing control signals, the signal routing device comprising: 
       a probe light source configured to generate probe lights formed by a series of sub-probe lights with variable desired wavelengths for respective time-slots, in synchronization with the high speed multiplexed signal lights;  
       a wavelength converter configured to receive the probe lights from the probe lights source and the high speed multiplexed signal lights, and to convert the prescribed identical wavelength of the high speed multiplexed signal lights in each time-slot into a prescribed wavelength of a probe light in a corresponding time-slot so as to obtain wavelength division multiplexed signal lights; and  
       a wavelength demultiplexer configured to wavelength division demultiplex the wavelength division multiplexed signal lights obtained by the wavelength converter, and to output demultiplexed signal lights;  
       wherein the probe light source has:  
       a plurality of sub-probe light sources configured to respectively generate the sub-probe lights with prescribed different wavelengths for respective time-slots;  
       a multiplexer configured to multiplex the sub-probe lights generated by the plurality of sub-probe light sources; and  
       a phase different giving unit configured to give phase differences corresponding to time-slot positions to the sub-probe lights multiplexed by the multiplexer, and to sequentially output the sub-probe lights with the phase differences in correspondence to respective time-slots, such that a sub-probe light with a desired wavelength is outputted in correspondence to a desired time-slot according to the routing control signals; and  
       the phase difference giving unit comprises:  
       a modulator for collectively modulating the sub-probe lights multiplexed by the multiplexer:  
       a first fiber grating for reflecting only a sub-probe light with a first desired wavelength according to the routing control signal and passing other sub-probe lights with wavelengths other than the first desired wavelength among the sub-probe lights modulated by the modulator;  
       a plurality of grating/delay pairs connected in series to which the other sub-probe lights passed by the first fiber grating are entered, an i-th grating/delay pair including: a delaying element for delaying those sub-probe lights that are passed by an (i−1)-th fiber grating, for a half of a prescribed phase difference between adjacent time-slots; and an i-th fiber grating for reflecting only a sub-probe light with an i-th desired wavelength according to the routing control signals and passing remaining sub-probe lights with wavelengths other than the i-th desired wavelength among those sub-probe lights that are delayed by the delaying element where i is an integer greater than one, such that all of the sub-probe lights with the prescribed different wavelengths are reflected by the first fiber grating and fiber grating of the plurality of grating/delay pairs; and  
       a circulator for inputting the sub-probe lights modulated by the modulator into the first fiber grating, and outputting the sub-probe lights reflected from the first fiber grating and the fiber gratings of the plurality of grating/delay pairs as the probe lights.  
     
     
       4. A signal routing device in a high speed transmission system, for time division demultiplexing high speed multiplexed signal lights in which signal lights with a prescribed identical wavelength are time division multiplexed in terms of time-slots, by converting the high speed multiplexed signal lights into low speed wavelength division multiplexed signal lights, and for outputting signal lights by distributing signal lights with desired wavelengths that constitute the low speed wavelength division multiplexed signals into desired time-slots according to routing control signals, the signal routing device comprising: 
       a probe light source configured to generate probe lights formed by a series of sub-probe lights with variable desired wavelengths for respective time-slots, in synchronization with the high speed multiplexed signal lights;  
       a wavelength converter configured to receive the probe lights from the probe light source and the high speed multiplexed signal lights, and to convert the prescribed identical wavelength of the high speed multiplexed signal lights in each time-slot into a prescribed wavelength of a probe light in a corresponding time-slot so as to obtain wavelength division multiplexed signal lights; and  
       a wavelength demultiplexer configured to wavelength division demultiplex the wavelength division multiplexed signal lights obtained by the wavelength converter, and to output demultiplexed signal lights;  
       wherein the probe light source has:  
       a plurality of sub-probe light sources configured to respectively generate the sub-probe lights with prescribed different wavelengths for respective time-slots;  
       a multiplexer configured to multiplex the sub-probe lights generated by the plurality of sub-probe light sources; and  
       a phase different giving unit configured to give phase differences corresponding to time-slot positions to the sub-probe lights multiplexed by the multiplexer and to sequentially output the sub-probe lights with the phase differences in correspondence to respective time-slots, such that a sub-probe light with a desired wavelength is outputted in correspondence to desired time-slot according to the routing control signals; and  
       the phase differences giving unit comprises:  
       a modulation signal generator for generating a plurality of modulation signals in which an (i+1)-th modulation signal has a wavelength which is a half of a wavelength of an i-th modulation signal where i is an integer;  
       a plurality of wavelength dependent modulators connected in series, for modulating the sub-probe lights multiplexed by the multiplexer by using the modulation signals, wherein the i-th modulation signal is supplied to than i-th wavelength dependent modulator, a first wavelength dependent modulator modulates a first half of the sub-probe lights at a first half period of a first modulation signal and modulates a second half of the sub-probe lights at a second half period of the first modulation signal, and a j-th wavelength dependent modulator modulates a half of the first half and a half of the second half of the sub-probe lights modulated by a (j−-1)-th wavelength dependent modulator at a first half period of a j-th modulation signal and modulates a remaining half of the first half and a remaining half of the second half of the sub-probe lights modulated by the (j−1)-th wavelength dependent modulator signal, where j is an integer greater than one, such that the sub-probe lights with wavelengths corresponding to respective time-slots are sequentially outputted from a last wavelength dependent modulator as the probe lights; and  
       a phase controller for variably controlling phases of the plurality of modulation signals from the modulation signal generator according to the routing control signals, such that the sub-probe light with the desired wavelength is outputted to the desired time-slot by the last wavelength dependent modulator.